The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
An engine combusts air and fuel to generate torque. Air flows into the engine through an intake system. The intake system may include a throttle valve and an intake manifold. Fuel is provided by one or more fuel injectors. The engine outputs torque to a transmission. The transmission transfers torque to one or more wheels. Exhaust resulting from combustion is expelled from the engine to an exhaust system.
An exhaust gas recirculation (EGR) system re-circulates exhaust back to the intake system. For exhaust to flow back to the intake system, pressure within the exhaust system must be greater than a pressure where the exhaust enters the intake system. The EGR system maybe controlled such that a target mixture of exhaust, air, and fuel is provided to each cylinder. The engine may not operate as intended when the target mixture is not maintained.